trained hard all winter in Lexington. In his first race as a three-year-old, he beat Clyde Van Dusen, a gelded son of Man o' War. On Derby Day, however, the track was deep and muddy. Because Thompson was suffering from appendicitis, an apprentice trainer prepared Blue Larkspur for the race and neglected to have him shod in "stickers" (special shoes for slippery mud). Blue Larkspur struggled to finish fourth, defeated by Clyde Van Dusen. Later in his 3-year-old season, however, Blue Larkspur convincingly won the one-mile Withers Stakes. Ridden by Mack Garner, he closed with a rush. He also took the 1½-mile Belmont Stakes, although he was again kicked at the post and the track was muddy. He was kicked yet again in a later start. Although he won the race, the wound became infected and he was sidelined for a time. Following the layoff, he won the Arlington Classic by five lengths. His season ended with a bowed tendon, but he has still been retrospectively regarded as 1929's Horse of the Year. In contemporary sources he is credited with being the year's leading money winner, but there is no record of a formal award. As a 4-year-old, Blue Larkspur raced three times (winning the Stars and Stripes Handicap and the Arlington Cup) before his leg again failed him. During his career (from 1928 to 1930) he raced 16 times with 10 wins, 3 seconds, and 1 third, earning $272,070. As a sire As a stallion at Idle Hour Stock Farm, Blue Larkspur excelled as he had on the track – especially with his daughters. Among his progeny was Oedipus, the 1950 and 1951 American steeplechase champion. Blue Larkspur made the broodmare sires list every year from 1944 through 1960, with his daughters producing 114 stakes winners and six champions. This may be because he is thought to have been a carrier of the X factor, a genetic trait which causes an extraordinarily large heart, and is only passed on to a stallion's daughters via the x-chromosome, although the basis of this theory has not been scientifically proven and dismissed in scientific circles. Blue Larkspur also produced the Hall of Famer Myrtlewood and Blue Denim, a mare who produced six stakes winners. Blue Denim's most important offspring was her daughter Ampola, who never won a stakes race but became one of the Stud Book's most important foundation mares for Gertrude